WordPress & WooCommerce Payment Gateway Expert Needed

We are looking for an experienced WordPress/WooCommerce developer with strong payment gateway and troubleshooting experience to diagnose and fix issues on our existing eCommerce website. Our payment gateway and required plugins have already been installed and configured, but the website is still experiencing transaction problems. Some payments are being blocked, and customers are receiving errors or unsuccessful responses during checkout. Scope of Work The selected developer will be responsible for: Diagnose why certain transactions are being blocked or declined. Investigate payment gateway error messages and response codes. Check the complete WooCommerce checkout and payment flow. Review payment gateway plugin configuration. Identify conflicts between the gateway plugin, WooCommerce, theme, or other plugins. Check API credentials, webhooks, callback URLs, and gateway communication. Review WordPress/WooCommerce logs for payment-related errors. Check server-side errors, PHP configuration, caching, firewall, security plugins, and other possible causes. Determine whether the issue is coming from the website, plugin, server, gateway configuration, or transaction request/response. Fix checkout errors without affecting the existing website design or functionality. Properly test the payment process after completing the fixes. Ensure successful transactions are correctly recorded in WooCommerce and order statuses update properly. Required Experience We are specifically looking for someone with proven experience in: WordPress WooCommerce Payment gateway integrations Payment gateway API troubleshooting Webhooks and callback troubleshooting PHP and WordPress debugging WooCommerce logs and error analysis Plugin conflict troubleshooting Server/security-related checkout issues High-risk or restricted-category eCommerce payment processing is a strong advantage Important This is not a new website development project. The website and payment gateway are already set up. We need an expert who can investigate the existing setup, identify the exact reason transactions are being blocked or returning errors, and fix the problem correctly. Please do not apply if your experience is limited to basic WordPress design or simply installing plugins. We need someone with advanced technical troubleshooting and payment gateway integration experience. When Applying, Please Include: Your experience troubleshooting WooCommerce payment gateway errors. Which payment gateways you have integrated or repaired. Examples of similar transaction/checkout issues you have solved. Your experience with API logs, webhooks, PHP errors, and server-side troubleshooting. Your availability to begin immediately. We are looking for someone who can start as soon as possible and focus on finding the root cause rather than applying temporary fixes.